Is there anything to do about a known rapist walking free?

There’s a guy in my neighborhood who I’ve known for years to be a rapist. This I know because I know him personally and I hear accounts from females who have been with him. He invites them over to his house, gives them liquor (not sure if he laces it) but the girls end up passing out and when they wake up, they realize that they’ve been raped. There have been talks of sex tapes ending up on the internet. I know guys who can also testify to this rapist’s behavior with other women. I know plenty of girls this has happened to at the hands of this guy, most of them underage at the time. I also know that they’re very scared of coming forward because of the shame and the amount of time that has passed since then. Meanwhile this guy continues to do these things and still continues to walk free. They say Karma is a bitch but things are occurring while we wait for Karma to take place. I really want to go to the guy’s house with my crew and administer some street justice if you know what I mean, but would much rather take a more effective, legal approach, if that’s possible. What can be done to bring justice without putting those girls out there to be embarassed? None are willing to testify against him and they all would rather move on with their life. I wanna see him get put away for a long time so that he can’t do this to any more females out there. Advice anyone??